Mechanical structure design
of the XY stage is designed in order to fit the current Olympus microscope.
For sample positioning, the stage was designed with considerations of
four major requirements defined earlier: proper travel range, small parasitic
motion, and short transient time response. The stage must have a central
aperture of about 2" diameter for white light illumination. Therefore,
a custom designed stage was necessary. For less friction and higher stiffness,
air bearing from Newway Precision is chosen. Coefficient of friction for
it is .00001. Stiffness for air bearing is 2,000,000 lb/in. With this
configuration, the expected air gap change is less than 2 micron. All
components were bolted together using various size threaded screws and
positioned with clearance holes. Linear Encoder from MicroE Systems is
selected for its high resolution of 0.078 micron and its compactness.
Linear motor from Aerotech is chosen for actuation for its high power
and less friction.